Vehicle driving control system

ABSTRACT

A vehicle driving control system has an automatic driving mode that enables traveling without a driver&#39;s operation. The vehicle driving control system includes a driver monitor that monitors a driver in a vehicle compartment, and detects a driver state, a driver state determining unit that determines, based on the driver state, whether the driver is in a state capable of driving normally, a retreat mode controller that controls a retreat mode that causes an own vehicle to travel for retreat to a place where the own vehicle can safely stop when it is determined, during traveling under the automatic driving mode, that the driver is not in the state capable of driving normally, and a retreat mode canceler that cancels the retreat mode when it is determined, during the travel for retreat, that the driver has returned to the state capable of driving normally.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNo. 2019-25795 filed on Feb. 15, 2019, the entire contents of which arehereby incorporated by reference.

BACKGROUND

The technology relates to a vehicle driving control system having anautomatic driving mode for enabling traveling without requiring adriver's driving operation.

A system having an automatic driving mode for enabling traveling withoutrequiring a driver's driving operation has been recently developed to beput into practical use for vehicles such as automobiles. In an automaticdriving vehicle as described above, when a system determines that it isdifficult to continue automatic driving due to malfunction of thevehicle or the like, a driver is required to take over driving andperform manual driving.

In order to reduce a risk that a driver is not capable of taking overdriving in spite of such a takeover request from an automatic drivingmode to manual driving due to deterioration of the driver's physicalcondition or the like, it has been known that a vehicle is provided witha retreat mode for automatically stopping the vehicle on behalf of thedriver, for example, as disclosed in Japanese Unexamined PatentApplication Publication (JP-A) No. 2016-196285.

SUMMARY

An aspect of the technology provides a vehicle driving control systemhaving an automatic driving mode that enables traveling without adriving operation by a driver. The system includes a driver monitor, adriver state determining unit, a retreat mode controller, and a retreatmode canceler. The driver monitor is configured to monitor, as thedriver, an occupant who can perform a driving operation in a vehiclecompartment, and detect a driver state. The driver state determiningunit is configured to determine, based on the driver state, whether thedriver is in a state capable of driving normally. The retreat modecontroller is configured to control a retreat mode that causes the ownvehicle to travel for retreat to a place where the own vehicle cansafely stop when the driver state determining unit determines, duringtraveling under the automatic driving mode, that the driver is not inthe state capable of driving normally. The retreat mode canceler isconfigured to cancel the retreat mode when the driver state determiningunit determines, during the travel for retreat, that the driver hasreturned to the state capable of driving normally.

An aspect of the technology provides a vehicle driving control system.The system includes circuitry configured to operate an automatic drivingmode for enabling traveling without requiring a driving operation by adriver. The circuitry is configured to monitor, as the driver, anoccupant who can perform a driving operation in a vehicle compartment,and detect a driver state. The circuitry is configured to determine,based on the driver state, whether the driver is in a state capable ofdriving normally. The circuitry is configured to control a retreat modefor causing the own vehicle to travel for retreat to a place where theown vehicle can safely stop when it is determined, during travelingunder the automatic driving mode, that the driver is not in the statecapable of driving normally. The circuitry is configured to cancel theretreat mode when it is determined, during the travel for retreat, thatthe driver has returned to the state capable of driving normally.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification. The drawings illustrate example embodimentsand, together with the specification, serve to explain the principles ofthe disclosure.

FIG. 1 is an overall configuration diagram of a driving control system;

FIG. 2 is a block diagram illustrating functions of an automatic drivingcontrol device;

FIG. 3 is an explanatory diagram illustrating transition of a drivingmode;

FIG. 4 is a flowchart illustrating driving mode transition processing;and

FIG. 5 is a subsequent flowchart of the flowchart in FIG. 4.

DETAILED DESCRIPTION

A description is given below of some embodiments of the technology withreference to the accompanying drawings. Note that the followingdescription is directed to illustrative examples of the technology andnot to be construed as limiting to the technology. Factors including,without limitation, numerical values, shapes, materials, components,positions of the components, and how the components are coupled to eachother are illustrative only and not to be construed as limiting to thetechnology. Further, elements in the following embodiments which are notrecited in a most-generic independent claim of the disclosure areoptional and may be provided on an as-needed basis. The drawings areschematic and are not intended to be drawn to scale.

A conventional system having an automatic driving mode has been designedso that once a driving mode is transitioned to a retreat mode andtraveling for retreat is started, the retreat mode cannot be canceleduntil a cancel switch is pushed or the like in order to prevent thetraveling for retreat from being interrupted by an erroneous operation.

For this reason, when the automatic driving mode has transitioned to theretreat mode due to the driver's temporary inattentive driving or drowsydriving, or when the automatic driving mode transitions to the retreatmode due to deterioration of the driver's physical condition, but thedriver's physical condition then recovers to a normally drivablephysical condition before the vehicle reaches a retreat point, thedriver has to wait until the vehicle reaches the retreat point and theretreat mode is canceled, which may make the driver feel bothered.

Therefore, it is desirable to provide a vehicle driving control systemthat can safely cancel a retreat mode according to the state of a drivereven halfway through traveling for retreat after an automatic drivingmode has been transitioned to the retreat mode.

An embodiment of the technology will be described below with referenceto the drawings. FIG. 1 is an overall configuration diagram of a drivingcontrol system. The driving control system 1 illustrated in FIG. 1 isinstalled in a vehicle such as an automobile, and enables drivingsupport for supporting a driver's driving operation and automaticdriving that does not require the driver's driving operation.Specifically, the driving control system 1 is configured by connectingan automatic driving control device 100 serving as a main component, anexternal environment recognition device 10, a positioning device 20, amap information processing device 30, a driver monitoring device 40, abraking/driving control device 50, a steering control device 60, aninformation presenting device 70 and the like to one another through acommunication bus 15 in a network connection style.

The external environment recognition device 10 recognizes an externalenvironment around a vehicle (own vehicle) in which the driving controlsystem 1 is installed. The external environment recognition device 10includes various devices configured to recognize an environment, such asa camera unit 11 and a radar device 12 such as a millimeter wave radaror a laser radar. The external environment recognition device 10recognizes an external environment around the own vehicle based ondetection information on objects around the own vehicle detected by thecamera unit 11, the radar device 12, etc., traffic information acquiredby infrastructure communication such as road-to-vehicle communicationand vehicle-to-vehicle communication, position information of the ownvehicle measured by the positioning device 20, map information from themap information processing device 30, and the like.

In the external environment recognition device 10, for example, when astereo camera including two cameras configured to capture images of thesame object from different viewpoints is mounted as the camera unit 11in the own vehicle. The external environment recognition device 10performs stereo processing on a pair of right and left images capturedby the stereo camera, to recognize the external environmentthree-dimensionally. The camera unit 11 as the stereo camera isconfigured, for example, by arranging two shutter-synchronized colorcameras each having an imaging element such as CCD or CMOS on right andleft sides in a vehicle width direction with a predetermined baselinelength in the vicinity of a room mirror located at an upper part of thevehicle compartment inside the windshield.

The pair of right and left images captured by the camera unit 11 as thestereo camera is subjected to matching processing to determine a pixelshift amount (parallax) at corresponding positions between the right andleft images, and the pixel shift amount is converted into luminance dataor the like to generate a distance image. Points on the distance imageare coordinate-transformed to points in a real space with the ownvehicle centered therein according to the principle of triangulation,and lane lines (lane) of a road on which the own vehicle travels,obstacles, vehicles traveling ahead of the own vehicle, etc., arethree-dimensionally recognized.

Road lane lines as a lane can be recognized by extracting a point groupas candidates for lane lines from an image and calculating a straightline or a curved line connecting the candidate points. For example,within a lane line detection region set on the image, edges which changein luminance by a predetermined value or more on a plurality of searchlines set in a horizontal direction (vehicle width direction) aredetected, and a pair of a lane line start point and a lane line endpoint are detected for each search line, whereby an intermediate regionbetween the lane line start point and the lane line end point isextracted as lane line candidate points.

Time-series data of spatial coordinate positions of lane line candidatepoints based on a vehicle movement amount per unit time are processed tocalculate a model approximating the right and left lane lines, therebyrecognizing the lane lines. As a lane line approximating model, anapproximate model obtained by connecting linear components obtained bythe Hough transform, or a model approximated by a curve such as aquadratic equation can be used.

The positioning device 20 mainly performs positioning based on signalsfrom a plurality of navigation satellites such as Global NavigationSatellite System (GNSS) satellites, and detects the vehicle position ofthe own vehicle. When the positioning accuracy deteriorates due to acapturing state of signals (radio waves) from satellites, the influenceof multipath caused by reflection of radio waves or the like, thepositioning device 20 detects the vehicle position of the own vehicle byperforming the positioning based on autonomous navigation usingin-vehicle sensors such as a gyro sensor 22 and a vehicle speed sensor23 in combination.

According to the positioning based on the plurality of navigationsatellites, signals containing information on the orbit, time, etc.,transmitted from the navigation satellites are received via a receiver21, and the own position of the own vehicle is calculated as an absoluteposition containing longitude, latitude, altitude, and time informationbased on the received signals. Furthermore, according to the positioningbased on the autonomous navigation, the position of the own vehicle as arelative positional change is measured based on the traveling azimuth ofthe own vehicle detected by the gyro sensor 22 and the moving distanceof the own vehicle calculated from a vehicle speed pulse output from thevehicle speed sensor 23.

The map information processing device 30 includes a map database DB, andspecifies the position on map data of the map database DB from positiondata of the own vehicle measured by the positioning device 20 andoutputs the specified position. The map database DB is a database thatholds a high-precision map created for control of traveling containingautomatic driving, and is stored in a large-capacity storage medium suchas a hard disk drive (HDD) or a solid state drive (SSD).

Specifically, the high-precision map is configured as amulti-dimensional map (dynamic map) that holds, in multiple layers,static information such as road shapes and connection relationshipsamong roads and dynamic information such as traffic informationcollected by infrastructure communication. Road data include the typesof road lane lines, the number of traveling lanes, widths of thetraveling lanes, point sequence data indicating the center position in awidth direction of the traveling lane, curvature of the traveling lane,a traveling azimuth angle of the traveling lane, a speed limit, etc.,and are stored together with attribute data such as data reliability anddata update date.

Further, the map information processing device 30 performs maintenancemanagement of the map database DB, verifies nodes, links, and datapoints of the map database DB to keep them in an up-to-date state at alltime, and creates and adds new data for areas for which no data existson the database, thereby configuring a more detailed database. Update ofdata and addition of new data in the map database DB are performed bycollating the position data measured by the positioning device 20 withthe data stored in the map database DB.

The driver monitoring device 40 functions as a driver monitor configuredto monitor, as a driver, an occupant who is capable of performing adriving operation in a vehicle compartment, with respect to theautomatic driving control device 100. The driver monitoring device 40detects a driver state, and transmits the detected driver state to theautomatic driving control device 100. The driver state includes thedriver's wakefulness level and physical condition, a motion associatedwith a driver's driving operation, and the like. The driver state isdetected by a plurality of sensors such as a visual sensor 41, abiological sensor 42, and a cancel switch 43 for canceling the retreatmode to be described later, which are installed in the vehicle. Acamera, a near infrared LED, a radar, an ultrasonic sensor, or the likeinstalled in the vehicle is used as the visual sensor 41. A camera, anear infrared LED, a radar, an ultrasonic sensor, a temperature sensor,a vibration sensor, or the like is used as the biological sensor 42.

The driver monitoring device 40 detects a driver's facial expression, adriver's hand motion, etc., by the visual sensor 41, and also detectsbiological information such as the presence or absence of driver'sbreathing, heart rate, blood pressure, body temperature, and brainwaves. As described later, the automatic driving control device 100determines, based on information from the driver monitoring device 40,whether the driver is in a state capable of driving normally.

The braking/driving control device 50 controls traveling driving forceto be generated by an electric motor or an internal combustion engine,and also controls the traveling speed of the own vehicle, switchingbetween forward driving and reverse driving, braking, and the like. Forexample, the braking/driving control device 50 controls an operatingstate of the engine based on signals from various sensors configured todetect the operating state of the engine and various control informationacquired via the communication bus 150, and controls braking devices(not illustrated) for four wheels independently of the driver's brakingoperation, based on a brake switch, wheel speeds of the four wheels, asteering angle, a yaw rate, and other information on the vehicle.Furthermore, the braking/driving control device 50 calculates brakefluid pressure of each wheel, based on braking force of each wheel, andperforms control of an anti-lock braking system, sideslip preventioncontrol and the like.

The steering control device 60 controls the steering torque by anelectric power steering device (EPS) 61 provided in a steering system,for example, based on the vehicle speed, the driver's steering torque,the steering angle, the yaw rate, and other information on the vehicle.The control of the steering torque is executed as current control forthe electric motor of the EPS device 61 that realizes a target steeringtorque for making the actual steering angle coincide with the targetsteering angle. The EPS device 61 uses the target steering torque fromthe steering control device 60 as an instruction torque to controldriving current of the electric motor corresponding to the instructiontorque by PID control, for example.

The information presenting device 70 is a device configured to controloutputs of an alarm when abnormality occurs in various devices of thevehicle, an alarm for alerting the driver, and output of various kindsof information to be presented to the driver. For example, warnings andcontrol information are presented by using at least one of a visualoutput such as a monitor, a display or an alarm lamp, or an auditoryoutput such as a speaker or a buzzer. During execution of the travelingcontrol containing automatic driving, the information presenting device70 presents a control state of the traveling control to the driver, andwhen the traveling control containing the automatic driving is suspendedby a driver's operation, the information presenting device 70 presents adriving state at that time to the driver.

Next, the automatic driving control device 100 serving as a maincomponent of the driving control system 1 will be described. When thedriver operates a switch, a panel (not illustrated) or the like toselect the driving support mode for supporting the driver's drivingoperation or the automatic driving mode requiring no driver's drivingoperation, when the driving mode is the manual driving mode in which thedriver drives the own vehicle by performing all the driving operationssuch as steering, acceleration and braking, the automatic drivingcontrol device 100 performs traveling control via the braking/drivingcontrol device 50 and the steering control device 60 based on theinformation from the external environment recognition device 10, thepositioning device 20, and the map information processing device 30.

Note that in the present embodiment, the driving support mode means adriving mode which automatically performs at least one ofacceleration/deceleration control or steering control, with the driverbeing required to hold the steering wheel or steer. The driving supportmode contains partially automatic driving. On the other hand, theautomatic driving mode means a driving mode presupposing hands-offdriving in which the driver does not touch the steering wheel, and is aconditional automatic driving mode in which all of theacceleration/deceleration control and the steering control areautomatically performed in an operation region in design where theautomatic driving function operates normally. In the automatic drivingmode, when it is difficult to continue the operation by the system, thedriving is entrusted to the driver.

The automatic driving control device 100 includes a control functionunit associated with each operation mode as described above. FIG. 2 is ablock diagram illustrating functions of the automatic driving controldevice. As illustrated in FIG. 2, the automatic driving control device100 includes a driving mode transition controller 101, a driver statedetermining unit 102, an override detector 103, a driving controller104, a retreat mode controller 105, and a retreat mode canceler 106. Thedriving controller 104 mainly performs control in the automatic drivingmode, and also performs control in the driving support mode.

The driving mode transition controller 101 determines the driving modeof the own vehicle according to an operation input by the driver from adriving mode setting switch, an operation panel, or the like, andnotifies the driving controller 104 of the driving mode. In the presentembodiment, the operation mode is set to the manual driving mode in aninitial state when the system is activated, and the driving modetransition controller 101 transitions the driving mode among the manualdriving mode, the driving support mode, and the automatic driving modebased on the information from the driver state determining unit 102 andthe override detector 103.

Based on the driver state detected by the visual sensor 41 and thebiological sensor 42 in the driver monitoring device 40 as the drivermonitor, the driver state determining unit 102 determines whether thedriver can normally drive the own vehicle. For example, as a driverstate, a visual-line behavior based on movement of a virtual image on acornea caused by a driver's eye movement, the wakefulness level based onvariation of the visual-line behavior and change of the pupil area, thepresence or absence of driver's breathing, biological information suchas heart rate, blood pressure, body temperature and brain waves,driver's face orientation, motion of driver's hands, etc. are detected.The driver state determining unit 102 determines whether the driver cannormally drive the own vehicle based on these pieces of information.

When the driver state determining unit 102 detects, from the orientationof the driver's face, an eye-opening state, and change in the directionof the visual line, that the driver is at least gazing in a travelingdirection, the driver state determining unit 102 determines that thedriver is in the state capable of driving normally. On the other hand,when the driver state determining unit 102 detects that the driverperforms inattentive driving while looking in a direction other than thetraveling direction for a predetermined period of time or more, althoughthe driver does not change the lane or there is no vehicle on anadjacent lane, or performs drowsy driving, with the pupil area decreasedto a threshold value or less for a predetermined period of time or more,or detects that the driver's biological information is out of a presetreference value, the driver state determining unit 102 determines thatthe driver's health condition has deteriorated and the driver is not inthe state capable of driving normally.

After determining that the driver's health condition has deterioratedand thus the driver is not in the state capable of driving normally, thedriver state determining unit 102 checks the driver state again todetermine whether the driver's health condition has recovered to thenormal state and the driver has returned to the state capable of drivingnormally. For example, when detecting that the driver is gazing in thetraveling direction, and further detecting at least one of the statethat the driver is holding the steering wheel, or the state that themotion of the driver's hands is the same as a pre-registered specifichand motion (hand gesture), the driver state determining unit 102determines that the driver's health has been recovered and the driverhas returned to the state capable of driving normally.

The override detector 103 detects an override operation for cancelingthe automatic driving mode and transitioning to the manual driving modeby the driver. For example, when the driver takes an action such asholding the steering wheel, steering with a steering torque of a setvalue or more, stepping on a brake pedal, or stepping on an acceleratorpedal during traveling under the automatic driving, the overridedetector 103 detects these driver's actions as an override operationbased on sensing information from a touch sensor, a steering torquesensor or the like, and the information from the driver monitoringdevice 40, and notifies the driving mode transition controller 101.

When the driving mode notified from the driving mode transitioncontroller 101 is the automatic driving mode, and a road condition, ageographical condition, an environmental condition, etc., satisfy anautomatic driving condition, the driving controller 104 automaticallyperforms the acceleration/deceleration control and the steering controlof the own vehicle. In the automatic driving, when a destination and atraveling route are specified in advance, automatic traveling isperformed to the destination along the traveling route whileappropriately setting the vehicle speed according to a surroundingtraffic environment, the distances to other vehicles, and a lane. Whenneither a destination nor a traveling route is specified, automatictraveling is performed along the lane.

Note that when a driver's override operation is detected by the overridedetector 103, the automatic driving by the driving controller 104 isstopped, and the driving mode is transitioned from the automatic drivingmode to the manual driving mode.

When a condition under which the automatic driving can be continued(automatic driving condition) is not satisfied during the travelingunder automatic driving, the driving controller 104 outputs a takeoverrequest for requesting the driver to take over the driving. For example,when it becomes difficult to continue the automatic driving becauseabnormality occurs in a part of the system or the traveling region ofthe vehicle is outside the operation range of the automatic driving orthe like, or when the driver state determining unit 102 detects driver'sinattentive driving or drowsy driving or determines that the driver isnot in the state capable of driving normally because deterioration ofdriver's physical condition is detected, it is determined that theautomatic driving condition is not satisfied, control information on thevehicle position and speed, etc., in automatic driving up to that timepoint is stored, and the takeover request for requesting the driver totake over the driving is output.

The takeover request is notified to the driving mode transitioncontroller 101, and also alerted to the driver via the informationpresenting device 70. When the driver reacts to the alert, to confirmforward and operates the steering wheel, the brake pedal or the like,alarm cancel is instructed from the driving mode transition controller101 to the information presenting device 70, and stop of the control inthe automatic driving mode is instructed to the driving controller 104.As a result, the driving mode is transitioned from the automatic drivingmode to the manual driving mode to be controlled by the driverhimself/herself.

On the other hand, when the driver does not respond to the takeoverrequest, the driving mode transition controller 101 instructs thedriving controller 104 to stop the automatic driving, and also instructsthe retreat mode controller 105 to perform retreat traveling in theretreat mode. The retreat mode is one of risk reduction modes during theautomatic driving, and is a driving mode for searching a place (retreatplace) such as a roadside belt where the vehicle can be stopped safelyin the control state of the automatic driving until the time point whenthe takeover request is output, and causing the vehicle to travel to theretreat place. In the retreat mode, the retreat mode controller 105normally disables the driver's override operation and disables thetransition to the manual operation mode in order to ensure safetyagainst an operation unintended by the driver.

For example, even when a driver's override operation is detected by theoverride detector 103, the retreat mode controller 105 disables thedriver's override operation by ignoring the detection of the driver'soverride operation or by causing the override detector 103 to stopdetection of the override operation. When the driver turns on the cancelswitch 43 after the own vehicle has reached the retreat place and thedriver stops a traveling driving source such as the electric motor, theengine or the like, the retreat mode is canceled by the retreat modecanceler 106.

Even during the retreat mode, if the driver state determining unit 102determines that the driver can normally drive, the retreat mode canceler106 cancels the retreat mode, and makes the driver's override operationenabled, that is, detectable. By enabling the override operation, it ispossible to detect the driver's override operation even during theretreat traveling and transition the driving mode to the manual drivingmode, and further it is possible to transition the driving mode to thedriving support mode.

The retreat mode canceler 106 acquires control information for theautomatic driving until the driving mode has been transitioned to theretreat mode and control information until the retreat mode has beencanceled, from the driving controller 104 and the retreat modecontroller 105, respectively. Furthermore, the retreat mode canceler 106acquires external environment information around the own vehicle at thetime of cancellation of the retreat mode from the external environmentrecognition device 10. By the retreat mode canceler 106 determiningbased on these pieces of information whether the automatic traveling canbe resumed, it is possible to return to the automatic driving mode aftercanceling the retreat mode.

Here, the transition among the respective driving modes will bedescribed. FIG. 3 is an explanatory diagram illustrating the transitionof the driving mode. In the present embodiment, as illustrated in FIG.3, the transition among the respective driving modes includestransitions in a state ST1 and transitions in a state ST2.

The state ST1 represents a normal state before the transition to theretreat mode for risk reduction occurs, and the driving mode can betransitioned among a manual driving mode M1, a driving support mode AS1,and an automatic driving mode AT. The state ST2 represents a state afterthe retreat mode for risk reduction is canceled halfway, and the drivingmode can be transitioned between a manual driving mode M2 and a drivingsupport mode AS2.

The manual driving mode M1 and the manual driving mode M2 are the samemanual driving mode, but are different in the transition-allowablerange. Likewise, the driving support mode AS1 and the driving supportmode AS2 are the same driving support mode, but are different in thetransition-allowable range.

A retreat mode RM at the time of risk occurrence is interposed betweenthe state ST1 and the state ST2. When the driving mode transitions fromthe automatic driving mode AT to the retreat mode RM, there are a casewhere the driving mode transitions from the retreat mode RM to themanual driving mode M1 in the state ST1 because the retreat mode RM hasterminated, and a case where the retreat mode RM is canceled halfwaythrough the retreat mode RM, and the driving mode transitions from theretreat mode RM to the manual driving mode M2 in the state ST2.

When the driving mode transitions to the manual driving mode M1 in thestate ST1 because the retreat mode RM has terminated, the driving modecan be transitioned between the normal driving modes. For example, evenwhen the driving mode has transitioned to the retreat mode RM duringautomatic traveling to a destination, it is possible to confirm safetyat a retreat place and then resume the automatic traveling to thedestination.

On the other hand, when the driving mode transitions to the manualdriving mode M2 in the state ST2 halfway through the retreat mode RM,the transition-allowable driving mode is temporarily restricted. Onlythe transition between the manual driving mode M2 and the drivingsupport mode AS2 is possible until the restriction on the modetransition is canceled, and the automatic traveling in the automaticdriving mode AT is not permitted. When the restriction on the modetransition is canceled, the driving mode transitions from the state ST2to the state ST1.

For example, when the vehicle has traveled for a certain period of timein a state where the driver state determining unit 102 detects that thedriver confirms forward and holds the steering wheel, the retreat modecanceler 106 determines that a condition for canceling the restrictionon the mode transition is satisfied. As a result, the state ST2 istransitioned to the normal state ST1, and it is possible to perform thetransition among the manual driving mode M1, the driving support modeAS1, and the automatic driving mode AT.

Next, operations associated with the transition of the driving mode inthe driving control system 1 will be described focusing on the operationof the automatic driving control device 100. FIGS. 4 and 5 areflowcharts illustrating driving mode transition processing duringautomatic driving.

In the driving mode transition processing, the automatic driving controldevice 100 checks in first step S1 whether the automatic drivingcondition is not satisfied due to system abnormality, deterioration ofthe driver's physical condition or the like, and the automatic drivingcannot be continued. When the automatic driving condition is notsatisfied, the automatic driving control device 100 outputs a takeoverrequest for requesting the driver to take over the driving in step S2,and checks the driver's response to the takeover request based on theinformation from the driver monitoring device 40 in step S3.

When confirming that the driver has held the steering wheel in responseto the takeover request, the automatic driving control device 100 stopsthe automatic driving and exits the present processing from step S3. Asa result, the driving mode transitions from the automatic driving modeAT to the normal manual driving mode (the manual driving mode M1 in thestate ST1).

On the other hand, when the driver does not respond to the takeoverrequest, for example, when the driver cannot normally drive because thedriver's physical condition has deteriorated or the like, the automaticdriving control device 100 proceeds from step S3 to step S4, andtransitions from the control of the automatic driving mode AT to thecontrol of the retreat mode RM. In the control of the retreat mode RM,the driver's override operation is disabled, and the own vehicle isautomatically moved to the retreat place by automatic traveling.

In step S5, the automatic driving control device 100 sets a modetransition restriction flag for restricting the transition of thedriving mode, and checks in step S6 whether the retreat mode RM remainsuncanceled. As described above, the retreat mode RM is canceled when itis determined that the driver has returned to the state capable ofdriving normally, and the driver's override operation is enabled.

When the retreat mode RM remains uncanceled, the automatic drivingcontrol device 100 checks in step S7 whether the own vehicle has reachedthe retreat place and the vehicle speed decreases to zero. When thevehicle speed is not equal to zero, the processing returns to step S6,and when the vehicle speed becomes zero, the vehicle is stopped in stepS8.

After the own vehicle is stopped in step S8, the processing proceeds tostep S9, and the automatic driving control device 100 checks whether acondition for clearing the mode transition restriction flag (a conditionfor canceling the mode transition restriction) is satisfied. Forexample, when detecting that the traveling drive source such as theelectric motor or the engine is stopped and the cancel switch 43 isturned on after the vehicle stops, the automatic driving control device100 determines that the condition for canceling the mode transitionrestriction is satisfied, clears the mode transition restriction flag,and exits from the processing. As a result, the retreat mode RM isterminated, and the driving mode transitions to the manual driving modeM1 in the normal state ST1.

On the other hand, in step S6, when it is detected from the informationfrom the driver monitoring device 40 that the driver's physicalcondition becomes normal and the driver holds the steering wheel toapply a predetermined steering torque in the traveling direction, theautomatic driving control device 100 cancels the retreat mode RM in stepS10. As a result, the automatic traveling to the retreat place isstopped, and the driving mode transitions to the manual driving mode M2in the state ST2.

After the driving mode transitioning to the manual driving mode M2 instep S10, the processing proceeds to step S11, and the automatic drivingcontrol device 100 checks whether the driver sets the driving supportmode. When the driver sets the driving support mode, the automaticdriving control device 100 transitions the driving mode to the drivingsupport mode AS2 in the state ST2 in step S12.

The driving support mode AS2 in the state ST2 is a mode that cannot betransitioned to the automatic driving mode AT. When the driving supportmode AS2 is canceled in step S13, a loop in which the processing returnsto step S10 to transition to the manual driving mode M2 in the state ST2is formed. In the manual driving mode M2, when the driver is manuallydriving the vehicle without setting the driving support mode, theautomatic driving control device 100 checks in step S14 whether thecondition for clearing the mode transition restriction flag issatisfied.

The condition for clearing the mode transition restriction flag in thiscase is a condition for canceling the restriction on the manual drivingmode M2 in the state ST2 and transitioning the driving mode to themanual driving mode M1 of the state ST1. For example, when the vehicleis confirmed to have traveled for a certain period of time in a statewhere it is detected that the driver confirms forward and holds thesteering wheel, the automatic driving control device 100 clears the modetransition restriction flag and exits from the processing. As a result,the driving mode transitions from the manual driving mode M2 of thestate ST2 to the manual driving mode M1 in the normal state ST1.

As described above, in the present embodiment, even halfway through thetraveling for retreat after the driving mode has transitioned from theautomatic driving mode to the retreat mode, when it is determined fromthe driver state that the driver has returned to the normal drivablestate, the retreat mode is canceled. As a result, when the driver hasreturned to the normal state after transition to the retreat mode, thereis no need to wait until the vehicle stops and the retreat mode isterminated, and the retreat mode can be safely canceled without causingthe driver to feel bothered.

The driving control system 1 illustrated in FIG. 1 can be implemented bycircuitry including at least one semiconductor integrated circuit suchas at least one processor (e.g., a central processing unit (CPU)), atleast one application specific integrated circuit (ASIC), and/or atleast one field programmable gate array (FPGA). At least one processorcan be configured, by reading instructions from at least one machinereadable tangible medium, to perform all or a part of functions of theautomatic driving control device 100 including the driver statedetermining unit 102, the retreat mode controller 105, and the retreatmode canceler 106 (see FIG. 2). Such a medium may take many forms,including, but not limited to, any type of magnetic medium such as ahard disk, any type of optical medium such as a CD and a DVD, any typeof semiconductor memory (i.e., semiconductor circuit) such as a volatilememory and a non-volatile memory. The volatile memory may include a DRAMand an SRAM, and the nonvolatile memory may include a ROM and an NVRAM.The ASIC is an integrated circuit (IC) customized to perform, and theFPGA is an integrated circuit designed to be configured aftermanufacturing in order to perform, all or a part of the functions of themodules shown in FIGS. 1 and 2.

Although some embodiments of the technology have been described in theforegoing by way of example with reference to the accompanying drawings,the technology is by no means limited to the embodiments describedabove. It should be appreciated that modifications and alterations maybe made by persons skilled in the art without departing from the scopeas defined by the appended claims. The technology is intended to includesuch modifications and alterations in so far as they fall within thescope of the appended claims or the equivalents thereof.

1. A vehicle driving control system having an automatic driving modethat enables traveling without a driving operation by a driver, thevehicle driving control system comprising: a driver monitor configuredto monitor, as the driver, an occupant who can perform a drivingoperation in a vehicle compartment, and detect a driver state; a driverstate determining unit configured to determine, on a basis of the driverstate, whether the driver is in a state capable of driving normally; aretreat mode controller configured to control a retreat mode that causesan own vehicle to travel for retreat to a place where the own vehiclecan safely stop when the driver state determining unit determines,during traveling under the automatic driving mode, that the driver isnot in the state capable of driving normally; and a retreat modecanceler configured to cancel the retreat mode when the driver statedetermining unit determines, during the travel for retreat, that thedriver has returned to the state capable of driving normally.
 2. Thevehicle driving control system according to claim 1, wherein the retreatmode canceler enables a return to the automatic driving mode aftercanceling the retreat mode.
 3. The vehicle driving control systemaccording to claim 1, wherein when detecting on the basis of the driverstate that the driver is gazing at least in a traveling direction duringthe travel for retreat, the driver state determining unit is determinesthat the driver has returned to the state capable of driving normally.4. The vehicle driving control system according to claim 2, wherein whendetecting on the basis of the driver state that the driver is gazing atleast in a traveling direction during the travel for retreat, the driverstate determining unit is determines that the driver has returned to thestate capable of driving normally.
 5. The vehicle driving control systemaccording to claim 3, wherein the driver state determining unitdetermines that the driver has returned to the state capable of drivingnormally, when detecting at least one of a state that the driver isholding a steering wheel and a state that a driver's hand motion is sameas a pre-registered specific hand motion.
 6. The vehicle driving controlsystem according to claim 4, wherein the driver state determining unitdetermines that the driver has returned to the state capable of drivingnormally, when detecting at least one of a state that the driver isholding a steering wheel and a state that a driver's hand motion is sameas a pre-registered specific hand motion.
 7. The vehicle driving controlsystem according to claim 1, wherein the retreat mode canceler cancelsthe retreat mode when the driver state determining unit determines thatthe driver has returned to the state capable of driving normally andwhen the own vehicle travels for a certain period of time in a statewhere the driver confirms forward and holds a steering wheel.
 8. Thevehicle driving control system according to claim 2, wherein the retreatmode canceler cancels the retreat mode when the driver state determiningunit determines that the driver has returned to the state capable ofdriving normally and when the own vehicle travels for a certain periodof time in a state where the driver confirms forward and holds asteering wheel.
 9. The vehicle driving control system according to claim3, wherein the retreat mode canceler cancels the retreat mode when thedriver state determining unit determines that the driver has returned tothe state capable of driving normally and when the own vehicle travelsfor a certain period of time in a state where the driver confirmsforward and holds a steering wheel.
 10. The vehicle driving controlsystem according to claim 4, wherein the retreat mode canceler cancelsthe retreat mode when the driver state determining unit determines thatthe driver has returned to the state capable of driving normally andwhen the own vehicle travels for a certain period of time in a statewhere the driver confirms forward and holds a steering wheel.
 11. Thevehicle driving control system according to claim 5, wherein the retreatmode canceler cancels the retreat mode when the driver state determiningunit determines that the driver has returned to the state capable ofdriving normally and when the own vehicle travels for a certain periodof time in a state where the driver confirms forward and holds asteering wheel.
 12. The vehicle driving control system according toclaim 6, wherein the retreat mode canceler cancels the retreat mode whenthe driver state determining unit determines that the driver hasreturned to the state capable of driving normally and when the ownvehicle travels for a certain period of time in a state where the driverconfirms forward and holds a steering wheel.
 13. A vehicle drivingcontrol system comprising circuitry configured to operate in anautomatic driving mode for enabling traveling without a drivingoperation by a driver, the circuitry being configured to monitor, as thedriver, an occupant who can perform a driving operation in a vehiclecompartment, and detect a driver state, determine, on a basis of thedriver state, whether the driver is in a state capable of drivingnormally, control a retreat mode that causes the own vehicle to travelfor retreat to a place where the own vehicle can safely stop when it isdetermined, during traveling under the automatic driving mode that thedriver is not in the state capable of driving normally, and cancel theretreat mode when it is determined, during the travel for retreat, thatthe driver has returned to the state capable of driving normally.